1. Field Of The Invention
This invention relates to a cowl box of a vehicle.
2. Description Of The Prior Art
In a vehicle, such as an automobile, it is conventional that a cowl box extending in a transverse direction of the car body is provided above a dash panel which partitions an engine compartment at the front of a car body from a passenger compartment and that a lower rim of a front windshield is adhered to the cowl box. For example, Japanese Utility Model Registration Application Laid-Open Publication No. 60-160262 discloses a defroster duct provided between a cowl box and an instrument panel, with its nozzle at the upper surface of the instrument panel, so as to defrost a front windshield fixed to the cowl box.
In accordance with the recent trend of improving aerodynamic characteristics of a vehicle, the rearward inclination of front windshields is made larger by locating a cowl box point (a point intersection of a front windshield with a hood) lower in the front of the car body, a result of which being that the cowl box is also located lower.
In a head-on collision, it sometimes happens that when the front part of a vehicle is crushed, an engine exhibiting high rigidity is forced back toward the passenger compartment relatively uncrushed. In such a case, if a cowl box is located relatively low, its lower part hits against the engine which is moving back and is then crushed. However, if the impact of the colliding vehicles is large, the cowl box moves back, as it is crushed, together with the engine and a force is generated in a direction that tends to separate the cowl box and the front windshield.
If the cowl box has a broader width in a lengthwise direction of a car body, when it collides with the engine the amount of crushing (crushability) of its lower part is larger; in other words, it absorbs the impact and accordingly the force acting in a direction tending to separate the front windshield from the cowl box is reduced. In this case, however, the cowl box having a broader width necessarily has its rear part extending to the underside of an upper wall of the instrument panel and therefore it becomes necessary to increase the width (in the lengthwise direction of a car body) of the instrument panel so as to secure a required space for accommodating a defroster duct. This naturally requires a corresponding reduction in space for occupants, namely, the passenger compartment is narrowed.
The broader the width of the cowl box, the more a nozzle of the defroster duct at the upper wall of the instrument panel is shifted rearwardly of the car body and therefore, air cannot be blown upwardly from near the lower rim of the front windshield and it becomes difficult to defrost the lower part of the front windshield. This tendency is especially noticeable when the cowl box is located lower in the front of the car body and a rearward inclination of the front window glass is large. On the other hand, if the defroster duct has a bend so as to extend from the rear part toward the upper part of the cowl box, its nozzle can be open near the front edge of the cowl box but it becomes necessary to secure a space for accommodating the defroster duct above the cowl box. Therefore, the level of the upper wall of the instrument panel is correspondingly raised and the space for occupants is reduced.